Do I have to offer food overnight?

My chicks are 6ish weeks old. I still have them in a brooder and they free range all day. They also get crumbles throughout the day. By the time I put them away for the night, their crops are all bulging full. Do you think I still need to offer them food overnight? They do get water at night if they want it, but when they have food in their brooder they make a huge mess and their water is full of litter. If they don't, it stays fairly clean and the water stays drinkable.

From my experience, chickens sleep very heavily when it's dark and don't eat, especially if their crops are stuffed full when they go to roost for the night.

However, they DO eat when it's light outside and they're very early risers. That's one reason why many chicken owners keep a light on in the coop when then number of daylight hours drops below 14 hours (I think that's how many it is, sorry). With a light on in the coop and food available the chickens can keep their energy and egg laying going even if you don't let them out to roam and graze at the crack of dawn.